Heretofore, as a technique of this type, there has been known a winding apparatus disclosed in Patent Literature 1 indicated below. This apparatus is arranged to supply and wind a hoop material made of an aluminum strip or a copper strip and a round conductive wire or a flat rectangular conductive wire to configure a primary coil and a secondary coil respectively. For supplying these conductive wires, a winding frame is placed in a fixed position and will be rotated to sequentially produce the primary coil and the secondary coil by switching a plurality of conductive wires.